A modified P and O maximum power point tracking method with reduced steady-state oscillation and improved tracking efficiency

Abstract

This paper proposes a method to reduce the steady-state oscillation and to mitigate the probability of losing the tracking direction of the perturb and observed (P and O)-based maximum power point tracking (MPPT) for PV system. The modified scheme retains the conventional P and O structure, but with a unique technique to dynamically alter the perturbation size. At the same time, a dynamic boundary condition is introduced to ensure that the algorithm will not diverge from its tracking locus. The modified P and O is simulated in MATLAB Simulink and its performance is benchmarked using the standard MPPT efficiency ηMPPT calculation. Furthermore, the proposed concept is validated experimentally using a buck-boost converter, fed by a solar PV array simulator (PVAS). Based on the EN 50530 dynamic irradiance tests, the proposed method achieved an average ηMPPT almost 1.1% higher than the conventional P and O when irradiance changes slowly and about 12% higher under fast change of irradiance.